1. Field of the Invention
The invention relates to systems for providing backlight modules.
2. Description of the Prior Art
Currently, light emitting diodes (LEDs) are developed and applied to backlight modules for replacing conventional CCFLs since LEDs have advantages of small size and low power consumption. FIG. 1 is a schematic diagram of a backlight module 10 according to the prior art. The prior art backlight module 10 includes a light guide plate 12 and a plurality of LEDs 14, wherein the LEDs 14 are positioned at one of the edges of the light guide plate (LGP) 12. Light emitted from each LED 14 appears an emitting area, as shown in the area between the arrows. The emitting area has an divergence angle θ of about 110° to 120°. As a result, some portions between the LEDs, near the edge of the light guide plate 12, are especially dark because they are out of the emitting areas of the LEDs 14.
FIG. 2 is a spatial luminance diagram of a backlight module according to the prior art. The portion near the edge of the light guide plate has a clear difference between light and shade, which is called a fire-fly situation. Referring to FIG. 2, the length of the fire-fly area is about 0.7 mm, and therefore, about 0.7 mm length of the backlight module is not suitable for providing light to a display panel above the light guide plate 14, resulted in the reduction of the display area.
Therefore, to provide backlight modules, with improved fire-fly situation, which can meet the green product acquirement is still an important issue to the backlight module manufacturers.